How to pass a variable to actix-web guard() in Rust? - rust

Question

#[actix_rt::main]
async fn main() -> std::io::Result<()> {
let token = env::var("TOKEN").expect("Set TOKEN");
HttpServer::new(|| {
App::new()
.wrap(middleware::Logger::default())
.service(
web::resource("/")
.guard(guard::Header("TOKEN", &token))
.route(web::post().to(index))
)
})
.bind("127.0.0.1:8080")?
.run()
.await
}
The error is:
error[E0597]: `token` does not live long enough
I saw .data() in actix docs but that is for passing variables inside routes functions.
UPD:
If I add "move":
HttpServer::new(move || {
then just error changes:
error[E0495]: cannot infer an appropriate lifetime for borrow expression due to conflicting requirements
--> src/main.rs:50:58
|
50 | .guard(guard::Header("TOKEN", &token))
| ^^^^^^
|
note: first, the lifetime cannot outlive the lifetime `'_` as defined on the body at 42:21...
--> src/main.rs:42:21
|
42 | HttpServer::new(move || {
| ^^^^^^^
note: ...so that closure can access `token`
--> src/main.rs:50:58
|
50 | .guard(guard::Header("TOKEN", &token))
| ^^^^^^
= note: but, the lifetime must be valid for the static lifetime...
note: ...so that reference does not outlive borrowed content
--> src/main.rs:50:58
|
50 | .guard(guard::Header("TOKEN", &token))
| ^^^^^^
error: aborting due to previous error

Answer 1

actix-web creates many threads and each worker (in each thread) must get a copy of a variable. So using let token = token.clone(); and move.
After that each of these variables goes into fn_guard function. So once again move.
let token = env::var("TOKEN").expect("You must set TOKEN");
HttpServer::new(move || {
let token = token.clone();
App::new()
.wrap(middleware::Logger::default())
.service(
web::resource("/")
.guard(guard::fn_guard(
move |req| match req.headers().get("TOKEN") {
Some(value) => value == token.as_str(),
None => false,
}))
.route(web::post().to(index))
)
})
.bind("127.0.0.1:8080")?
.run()
.await
This works.
Can't get it working with only .guard(guard::Header("TOKEN", &token))